"Spot the Rock!" for Thursday, April 3, 2014

Hello, geo friends! We’re going to try something a little different for “Spot the Rock!” today. Thanks to Google Earth, we’ve got an aerial image for you to ponder. Can anyone guess where this is?

UPDATE: Location Revealed

Last week’s “Spot the Rock” featured a Google Earth image of the evaporation ponds at the Intrepid Potash, Inc. ‘solution’ mine in Grand County. These ponds are found roughly 3 miles east and nearly 1,700 feet below Dead Horse Point State Park in San Juan.

‘Potash’ refers to a group of potassium-bearing minerals, the most common of which is sylvite (potassium chloride). Potash is important for its use in fertilizer. Along with other salts, Potash minerals form through the evaporation of saline lakes or oceans. Intrepid produces potash from deeply-buried evaporites formed during the Pennsylvanian Period (~300 million years ago) in a restricted marine basin where seawater was concentrated, precipitated salt, and was subsequently diluted multiple times.

Here is how Intrepid describes their solution mining process:

Water is saturated with salt and the resulting brine is pumped through injection wells into the underground mine workings. The injected brine preferentially dissolves the potash from layers buried between 2,400 and 4,000 feet below the surface. As the brine preferentially dissolves the potassium, the double saturated potassium and salt brine becomes heavier than the salt saturated brine causing it to sink to low points in the mining caverns. Extraction wells are installed at the low points to pump the potash rich brine to the surface, where it is placed into 400 acres of shallow evaporation ponds just southwest of the mine. Blue dye, similar to food coloring, is added to the evaporation pond brines, to aid in absorption of sunlight. There, the water, aided by approximately 300 days of sunshine and an average of just five percent relative humidity evaporates, leaving potash and salt crystals in the pond.https://www.intrepidpotash.com/AboutUs/LocationsOperations/MoabUT.aspx